A verbal is a verb that acts like a different part of speech. Infinitives, gerunds, and participles are all types of verbals. An infinitive is a verbal consisting of to + a verb, and it acts like a subject, direct object, subject complement, adjective, or adverb in a sentence.
HeadOn is the brand name of a topical product claimed to relieve headaches. It achieved widespread notoriety in 2006 as a result of a repetitive commercial, consisting only of the tagline HeadOn. Apply directly to the forehead, stated three times in succession.
The head aboard a Navy ship is the bathroom. The term comes from the days of sailing ships when the place for the crew to relieve themselves was all the way forward on either side of the bowsprit, the integral part of the hull to which the figurehead was fastened.